Raleigh, N.C. — North Carolina State University police say they don't think a report of assault on campus Tuesday night is related to another report last week in which a woman said she was sexually assaulted.

The university sent a crime alert to students early Wednesday after a female student told police she was walking on Main Campus, near the north side of Daniels Hall, around 11 p.m. when a man carrying a black bag approached her, put his arm around her and tried talking to her.

The student sprayed the man with pepper spray, ran and called police.

The encounter is the third reported in a week.

Early Thursday, a student said she was sexually assaulted on campus near the university's Free Expression Tunnel while she was walking from a library.

Another student reported Saturday night that he was robbed at knifepoint, but Raleigh police have said that they can't yet say for sure whether it happened.

North Carolina State University Police Chief Jack Moorman said Wednesday that there doesn't appear to be a connection between Thursday's attack and Tuesday's report.

Authorities said the man who approached the student on Tuesday night was 19 to 20 years old and stood about 6 feet 3 inches tall. He had a full beard and was wearing a red sweatshirt with a black "S" and blue jeans at the time of the reported assault.

The man whom police are looking for in last week's sexual assault was in his early to mid-20s, stood 5 feet 10 inches tall and had short hair.

Still, campus police have heightened security for the rest of the semester, which ends May 9.

Moorman said students should be more vigilant and aware of their surroundings, walk along well-lit pathways and never walk alone at night. The university also offers the Safety Escort Program, which runs 10 p.m. to 4 a.m. nightly.